Mobil 1 5w-30, 6261 miles, Subaru WRX - Everything went up

[rexster]

I started running mobil 1 at my second oil change around 6,000 miles. I changed it every 3000 miles until last year when i figured i might as well try and extend it to 7500 which is what the Subaru recommends. My first analysis was done after 37,624 miles with 4427 miles on the oil. The numbers were all below normal so i let it go to 6261 miles this time. All the numbers are up quite a bit this time.

code:

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6261 / 4427 / Uni avg

ALUMINUM 4/ 3/ 3

CHROMIUM 1/ 1/ 1

IRON 14/ 9/ 8

COPPER 5/ 4/ 5

LEAD 7/ 1/ 5

TIN 0/ 1/ 1

MOLYBDENUM 92/ 59/ 71

NICKEL 0/ 0/ 0

MANGANESE 0/ 0/ 0

SILVER 0/ 0/ 0

TITANIUM 0/ 0/ 0

POTASSIUM 0/ 2/ 1

BORON 155/ 130/ 99

SILICON 15/ 11/ 7

SODIUM 3/ 4/ 6

CALCIUM 3195/ 3047/ 2577

MAGNESIUM 18/ 13/ 114

PHOSPHORUS 874/ 687/ 778

ZINC 1084/ 706/ 917

BARIUM 0/ 0/ 0





6261 / 4427



Sus Viscosity 60.5 / 57.5

Flashpoint 380 / 370

Fuel % < 0.5 / < 0.5

Antifreeze % 0 / 0

Water % 0 / 0

Insolubles 0.3 / 0.4

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Feedback from Blackstone: Silicon increased a little, and along with it, engine wear. The oil was run about 1,800 miles longer than the first sample, and that accounts for most of the increased wear. Silicon can often show problems developing at the air filtration, so we suggest checking this system on your engine. These metals are not enough above universal average levels to show a mechanical problem developing in the engine. No fuel dilution or coolant was found and insolubles were low showing good oil filtration. Other than the silicon, nothing unusual showed up at 43,885 miles.

The feedback only points out the silicone, but several other things are up as well. I'm going to check my air filter, but I'm pretty sure it's ok. Is there anything else that stands out to you guys as a potential problem? Should I let it go 7500 miles or should I change it more frequently?

thanks,
erik

[ July 11, 2005, 10:39 AM: Message edited by: 59 Vetteman ]

 

[buster]

I think it's the Si. Everything looks good otherwise. Keep trending....

 

[nicrfe1370]

Erik,

This isn't a bad report really, though it is a little higher than Subaru's usually are. In reality, you could probably do 7500 mile or longer OCI's with no ill effects. But , in case you're interested in top notch service from your oil and car for a long time, then continue reading. Back when I owned a WRX, I gathered all UOA's I could find from BITOG and other places and compiled them all into an Excel spreadsheet. What became clear is, on average, WRX's seemed to show excellent wear numbers regardless of oil up until approximately 4500-5000 miles. After 5000 miles, wear metals seemed to climb more steeply. Buster mentioned in a different post recently that he felt as though one should not try to push OCI's to their maximum in a turbocharged vehicle. I am with him on this one. Turbos (even water cooled ones) get too hot, and have tiny little holes that I would rather not see old oil plug up. I would stick with sub 5000 mile OCI's in your WRX. I would also consider, especially if you plan to run long OCI's, using Lube Control.

 

[AndyH]

rexster: Are you using a stock air filter or some sort of aftermarket drop-in or cone filter setup?

 

[rexster]

it's regular mobil 1, not the new extended mileage stuff. I hadn't looked at it from ppm/mileage. I was looking at the rates of change accross the two tests. Comparing the two, the mileage went up by 41%. What had me concerned was that iron was up 55%, lead was up 600%, moly up 55% and zinc was up 54%. So if these elements were increasing at a faster rate than the mileage that indicated a bad trend. But you're right that many things went down.

 

[rexster]

Stock air filter which was replaced at 30,000 miles.

Thanks for the heads up nicrfe1370, I think I'm going to go back to changing it every 4000 miles to keep everything low.

 

[jsharp]

If you look at the ppm/mileage the only mumber that's up much is lead. The iron is about the same as are the others, if not a bit lower. Even the silicon is lower if you measure it that way.


What version of M1 is this?